After a job well done, the South African star gave her new man a pat on the butt before heading into their car.

Charlize Theron gave boyfriend Sean Penn a pat on the butt while grocery shopping in L.A. on Jan. 22.4CRNS/O. Duran/FAMEFLYNET PICTURES

Theron and Penn were first rumored to be dating when they were spotted ringing in the New Year together in Hawaii. In a Jan. 18 blog post, Piers Morgan confirmed they were a couple by sharing a conversation he had with Penn at the Jan. 11 Help Haiti Home gala.

"At 2 a.m., Sean came over, and bear-hugged me," the Piers Morgan Live host wrote. "'Congrats on a great night,' I said. 'And congrats on Charlize too.' He laughed. 'She's a keeper, that's for sure . . . well, I'll do my best to keep her anyway!'"